Beam-switching capability indication in wireless networks that utilize beamforming

ABSTRACT

Disclosed are techniques for enhanced positioning methods that are suitable for use in a wireless network that utilizes beamformed communication. More particularly, a user equipment (UE) may determine a capability for a number of beam switches that the UE supports per slot for one or more slot types and transmit, to a network node, capability information indicating the capability for the number of beam switches that the UE supports per slot in slots having the one or more slot types. As such, the network node may transmit and the UE may receive one or more signals across a number of beams based on the capability indicated in the capability information for the number of beam switches per slot based on a slot type associated with a slot in which the one or more signals are transmitted.

CROSS-REFERENCE TO RELATED APPLICATION

The present application for patent claims the benefit of U.S.Provisional Patent Application No. 62/688,362 entitled “BEAM-SWITCHINGCAPABILITY INDICATION IN WIRELESS NETWORKS THAT UTILIZE BEAMFORMING,”filed Jun. 21, 2018, assigned to the assignee hereof, and expresslyincorporated herein by reference in its entirety.

TECHNICAL FIELD

Aspects described herein generally relate to wireless communicationsystems, and in particular, to indicating beam-switching capabilities toa network node in a wireless network that utilizes beamformedcommunication.

BACKGROUND

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service and a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax). There are presentlymany different types of wireless communication systems in use, includingCellular and Personal Communications Service (PCS) systems. Examples ofknown cellular systems include the cellular Analog Advanced Mobile PhoneSystem (AMPS), and digital cellular systems based on Code DivisionMultiple Access (CDMA), Frequency Division Multiple Access (FDMA), TimeDivision Multiple Access (TDMA), the Global System for Mobile access(GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard calls for higher data transferspeeds, greater numbers of connections, and better coverage, among otherimprovements. The 5G standard, according to the Next Generation MobileNetworks Alliance, is designed to provide data rates of several tens ofmegabits per second to each of tens of thousands of users, with 1gigabit per second to tens of workers on an office floor. Severalhundreds of thousands of simultaneous connections should be supported inorder to support large sensor deployments. Consequently, the spectralefficiency of 5G mobile communications should be significantly enhancedcompared to the current 4G standard. Furthermore, signaling efficienciesshould be enhanced and latency should be substantially reduced comparedto current standards.

Some wireless communication networks, such as 5G, support operation atvery high and even extremely-high frequency (EHF) bands, such asmillimeter wave (mmW) frequency bands (generally, wavelengths of 1 mm to10 mm, or 30 to 300 GHz). These extremely high frequencies may supportvery high throughput such as up to six gigabits per second (Gbps). Oneof the challenges for wireless communication at very high or extremelyhigh frequencies, however, is that a significant propagation loss mayoccur due to the high frequency. As the frequency increases, thewavelength may decrease, and the propagation loss may increase as well.At mmW frequency bands, the propagation loss may be severe. For example,the propagation loss may be on the order of 22 to 27 dB, relative tothat observed in either the 2.4 GHz, or 5 GHz bands.

Propagation loss is also an issue in Multiple Input-Multiple Output(MIMO) and massive MIMO systems in any band. The term MIMO as usedherein generally refers to both MIMO and massive MIMO. MIMO is a methodto multiply the capacity of a radio link by using multiple transmit andreceive antennas to exploit multipath propagation, which occurs becauseradio frequency (RF) signals not only travel by the shortest pathbetween the transmitter and receiver, which may be a line of sight (LOS)path, but also over a number of other paths as they spread out from thetransmitter and reflect off other objects such as hills, buildings,water, and the like on their way to the receiver. A transmitter in aMIMO system includes multiple antennas and takes advantage of multipathpropagation by directing these antennas to each transmit the same RFsignals on the same radio channel to a receiver. The receiver is alsoequipped with multiple antennas tuned to the radio channel that candetect the RF signals sent by the transmitter. As the RF signals arriveat the receiver (some RF signals may be delayed due to the multipathpropagation), the receiver can combine them into a single RF signal.Because the transmitter sends each RF signal at a lower power level thana single RF signal would be sent, propagation loss is also an issue in aMIMO system.

To address propagation loss issues in mmW band systems and MIMO systems,transmitters may use beamforming to extend RF signal coverage. Inparticular, transmit beamforming is a technique for emitting an RFsignal in a specific direction, whereas receive beamforming is atechnique used to increase receive sensitivity of RF signals that arriveat a receiver along a specific direction. Transmit beamforming andreceive beamforming may be used in conjunction with each other orseparately, and references to “beamforming” may hereinafter refer totransmit beamforming, receive beamforming, or both. Traditionally, whena transmitter broadcasts an RF signal, the RF signal is broadcasted innearly all directions determined by the fixed antenna pattern orradiation pattern of the antenna. With beamforming, the transmitterdetermines where a given receiver is located relative to the transmitterand projects a stronger downlink RF signal in that specific direction,thereby providing a faster (in terms of data rate) and stronger RFsignal for the receiver. To change the directionality of the RF signalwhen transmitting, a transmitter can control the phase and relativeamplitude of the RF signal broadcasted by each antenna. For example, atransmitter may use an array of antennas (also referred to as a “phasedarray” or an “antenna array”) that creates a beam of RF waves that canbe “steered” to point in different directions, without actually movingthe antennas. Specifically, the RF current is fed to the individualantennas with the correct phase relationship so that the radio wavesfrom the separate antennas add together to increase the radiation in adesired direction, while cancelling the radio waves from the separateantennas to suppress radiation in undesired directions.

To support position estimations in terrestrial wireless networks, amobile device can be configured to measure and report the observed timedifference of arrival (OTDOA) or reference signal timing difference(RSTD) between reference RF signals received from two or more networknodes (e.g., different base stations or different transmission points(e.g., antennas) belonging to the same base station). However, theunique challenges of heavy path-loss faced by mmW communication systemsnecessitate new techniques, which are not present in third generation(3G) and/or fourth generation (4G) wireless communication systems.Accordingly, there may be a need to enhance positioning methods that aretraditionally used in wireless networks to take into account the uniquechallenges that may arise with beamformed communication.

SUMMARY

The following presents a simplified summary relating to one or moreaspects and/or embodiments disclosed herein. As such, the followingsummary should not be considered an extensive overview relating to allcontemplated aspects and/or embodiments, nor should the followingsummary be regarded to identify key or critical elements relating to allcontemplated aspects and/or embodiments or to delineate the scopeassociated with any particular aspect and/or embodiment. Accordingly,the following summary has the sole purpose to present certain conceptsrelating to one or more aspects and/or embodiments relating to themechanisms disclosed herein in a simplified form to precede the detaileddescription presented below.

According to various aspects, a method a user equipment (UE) maycomprise determining a capability for a number of beam switches that theUE supports per slot for each slot of one or more slots based on a slottype of that slot and/or based on one or more other capabilitiesassociated with the UE to receive one or more signals across a number ofbeams. The method may also comprise transmitting, to a network node,capability information indicating the capability for the number of beamswitches that the UE supports per slot. The method may further comprisereceiving, at the UE, the one or more signals across the number of beamsbased on the capability indicated in the capability information for thenumber of beam switches per slot associated with a slot in which the oneor more signals are transmitted.

According to various aspects, a user equipment (UE) may comprise atleast one processor, at least one transmitter, and at least onereceiver. The at least one processor may be configured to determine acapability for a number of beam switches supported by the apparatus perslot for each slot of one or more slots based on a slot type of thatslot and/or based on one or more other capabilities associated with theUE to receive one or more signals across a number of beams. Thetransmitter may be configured to transmit, to a network node, capabilityinformation indicating the capability for the number of beam switchessupported by the apparatus per slot. The receiver may be configured toreceive the one or more signals across the number of beams based on thecapability indicated in the capability information for the number ofbeam switches per slot associated with a slot in which the one or moresignals are transmitted.

According to various aspects, a user equipment (UE) may comprise meansfor determining a capability for a number of beam switches that theapparatus supports per slot for each slot of one or more slots based ona slot type of that slot and/or based on one or more other capabilitiesassociated with the apparatus to receive one or more signals across anumber of beams. The UE may also comprise means for transmitting, to anetwork node, capability information indicating the capability for thenumber of beam switches that the UE supports per slot. The UE mayfurther comprise means for receiving the one or more signals across thenumber of beams based on the capability indicated in the capabilityinformation for the number of beam switches per slot associated with aslot in which the one or more signals are transmitted.

According to various aspects, a computer-readable medium may havecomputer-executable instructions for a user equipment (UE) recordedthereon. The computer-executable instructions may comprise one or moreinstructions causing the UE to determine a capability for a number ofbeam switches supported by the apparatus per slot for each slot of oneor more slots based on a slot type of that slot and/or based on one ormore other capabilities associated with the apparatus to receive one ormore signals across a number of beams. The computer-executableinstructions may also comprise one or more instructions causing the UEto transmit, to a network node, capability information indicating thecapability for the number of beam switches supported by the apparatusper slot. The computer-executable instructions may further comprise oneor more instructions causing the UE to receive the one or more signalsacross the number of beams based on the capability indicated in thecapability information for the number of beam switches per slotassociated with a slot in which the one or more signals are transmitted.

According to various aspects, a method of a network node may comprisereceiving capability information from a user equipment (UE) indicating acapability for a number of beam switches that the UE supports per slotfor each slot of one or more slots based on a slot type of that slotand/or based on one or more other capabilities associated with the UE toreceive one or more signals across a number of beams. The method mayalso comprise transmitting, to the UE, the one or more signals in aslot, wherein the one or more transmitted signals are transmitted acrossthe number of beams based on the capability indicated in the capabilityinformation for the number of beam switches per slot associated with theslot in which the one or more signals are transmitted.

According to various aspects, a network node may comprise a receiverconfigured to receive capability information from a user equipment (UE)indicating a capability for a number of beam switches that the UEsupports per slot for each slot of one or more slots based on a slottype of that slot and/or based on one or more other capabilitiesassociated with the UE to receive one or more signals across a number ofbeams. The network node may also comprise a transmitter configured totransmit, to the UE, the one or more signals in a slot, wherein the oneor more transmitted signals are transmitted across the number of beamsbased on the capability indicated in the capability information for thenumber of beam switches per slot associated with the slot in which theone or more signals are transmitted

According to various aspects, a network node may comprise means forreceiving capability information from a user equipment (UE) indicating acapability for a number of beam switches that the UE supports per slotfor each slot of one or more slots based on a slot type of that slotand/or based on one or more other capabilities associated with the UE toreceive one or more signals across a number of beams. The network nodemay also comprise means for transmitting, to the UE, the one or moresignals in a slot, wherein the one or more transmitted signals aretransmitted across the number of beams based on the capability indicatedin the capability information for the number of beam switches per slotassociated with the slot in which the one or more signals aretransmitted.

According to various aspects, a computer-readable medium may havecomputer-executable instructions for a network node recorded thereon.The computer-executable instructions may comprise one or moreinstructions causing the network node to receive capability informationfrom a user equipment (UE) indicating a capability for a number of beamswitches that the UE supports per slot for each slot of one or moreslots based on a slot type of that slot and/or based on one or moreother capabilities associated with the UE to receive one or more signalsacross a number of beams. The computer-executable instructions may alsocomprise one or more instructions causing the network node to transmit,to the UE, the one or more signals in a slot, wherein the one or moretransmitted signals are transmitted across the number of beams based onthe capability indicated in the capability information for the number ofbeam switches per slot associated with the slot in which the one or moresignals are transmitted.

Other objects and advantages associated with the aspects and embodimentsdisclosed herein will be apparent to those skilled in the art based onthe accompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the various aspects and embodimentsdescribed herein and many attendant advantages thereof will be readilyobtained as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings which are presented solely for illustration andnot limitation, and in which:

FIG. 1 illustrates an exemplary wireless communications system,according to various aspects of the disclosure.

FIGS. 2A and 2B illustrate example wireless network structures,according to various aspects of the disclosure.

FIG. 3 illustrates an exemplary base station and an exemplary UE in anaccess network, according to various aspects of the disclosure.

FIG. 4 illustrates an exemplary wireless communications system,according to various aspects of the disclosure.

FIG. 5 illustrates an exemplary wireless communications system,according to various aspects of the disclosure.

FIG. 6A is a graph showing the RF channel response at a UE over time,according to various aspects of the disclosure.

FIG. 6B illustrates an exemplary separation of clusters in Angle ofDeparture (AoD) according to various aspects of the disclosure.

FIGS. 7A, 7B, and 7C illustrate exemplary signaling flows in which a UEmay indicate beam-switching and other positioning-related capabilitiesto a network node that may transmit one or more positioning-relatedreference signals based on the indicated beam-switching and otherpositioning-related capabilities, according to various aspects of thedisclosure.

FIG. 8 illustrates a flowchart of an exemplary method performed by a UEfor indicating beam-switching capabilities according to various aspectsof the disclosure.

FIG. 9 illustrates a flowchart of an exemplary method performed by anetwork node for transmitting beamformed signals according to variousaspects of the disclosure.

DETAILED DESCRIPTION

Various aspects and embodiments are disclosed in the followingdescription and related drawings to show specific examples relating toexemplary aspects and embodiments. Alternate aspects and embodimentswill be apparent to those skilled in the pertinent art upon reading thisdisclosure, and may be constructed and practiced without departing fromthe scope or spirit of the disclosure. Additionally, well-known elementswill not be described in detail or may be omitted so as to not obscurethe relevant details of the aspects and embodiments disclosed herein.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect or embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or embodiments. Likewise, the terms“aspects” and “embodiments” do not require that all aspects orembodiments include the discussed feature, advantage, or mode ofoperation.

The terminology used herein describes particular aspects only and shouldnot be construed to limit any aspects disclosed herein. As used herein,the singular forms “a,” “an,” and “the” are intended to include theplural forms as well, unless the context clearly indicates otherwise.Those skilled in the art will further understand that the terms“comprises,” “comprising,” “includes,” and/or “including,” as usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Further, various aspects may be described in terms of sequences ofactions to be performed by, for example, elements of a computing device.Those skilled in the art will recognize that various actions describedherein can be performed by specific circuits (e.g., an applicationspecific integrated circuit (ASIC)), by program instructions beingexecuted by one or more processors, or by a combination of both.Additionally, these sequences of actions described herein can beconsidered to be embodied entirely within any form of non-transitorycomputer-readable medium having stored thereon a corresponding set ofcomputer instructions that upon execution would cause an associatedprocessor to perform the functionality described herein. Thus, thevarious aspects described herein may be embodied in a number ofdifferent forms, all of which have been contemplated to be within thescope of the claimed subject matter. In addition, for each of theaspects described herein, the corresponding form of any such aspects maybe described herein as, for example, “logic configured to” and/or otherstructural components configured to perform the described action.

As used herein, the terms “user equipment” (or “UE”), “user device,”“user terminal,” “client device,” “communication device,” “wirelessdevice,” “wireless communications device,” “handheld device,” “mobiledevice,” “mobile terminal,” “mobile station,” “handset,” “accessterminal,” “subscriber device,” “subscriber terminal,” “subscriberstation,” “terminal,” and variants thereof may interchangeably refer toany suitable mobile or stationary device that can receive wirelesscommunication and/or navigation signals. These terms are also intendedto include devices which communicate with another device that canreceive wireless communication and/or navigation signals such as byshort-range wireless, infrared, wireline connection, or otherconnection, regardless of whether satellite signal reception, assistancedata reception, and/or position-related processing occurs at the deviceor at the other device. In addition, these terms are intended to includeall devices, including wireless and wireline communication devices, thatcan communicate with a core network via a radio access network (RAN),and through the core network the UEs can be connected with externalnetworks such as the Internet and with other UEs. Of course, othermechanisms of connecting to the core network and/or the Internet arealso possible for the UEs, such as over a wired access network, awireless local area network (WLAN) (e.g., based on IEEE 802.11, etc.)and so on. UEs can be embodied by any of a number of types of devicesincluding but not limited to printed circuit (PC) cards, compact flashdevices, external or internal modems, wireless or wireline phones,smartphones, tablets, tracking devices, asset tags, and so on. Acommunication link through which UEs can send signals to a RAN is calledan uplink channel (e.g., a reverse traffic channel, a reverse controlchannel, an access channel, etc.). A communication link through whichthe RAN can send signals to UEs is called a downlink or forward linkchannel (e.g., a paging channel, a control channel, a broadcast channel,a forward traffic channel, etc.). As used herein the term trafficchannel (TCH) can refer to either an uplink/reverse or downlink/forwardtraffic channel.

According to various aspects, FIG. 1 illustrates an exemplary wirelesscommunications system 100. The wireless communications system 100, whichmay also be referred to as a wireless wide area network (WWAN), mayinclude various base stations 102 and various UEs 104. The base stations102 may include macro cells (high power cellular base stations) and/orsmall cells (low power cellular base stations). The macro cells mayinclude Evolved NodeBs (eNBs) where the wireless communications system100 corresponds to an LTE network, gNodeBs (gNBs) where the wirelesscommunications system 100 corresponds to a 5G network, and/or acombination thereof, and the small cells may include femtocells,picocells, microcells, etc.

The base stations 102 may collectively form a Radio Access Network (RAN)and interface with an Evolved Packet Core (EPC) or Next Generation Core(NGC) through backhaul links. In addition to other functions, the basestations 102 may perform functions that relate to one or more oftransferring user data, radio channel ciphering and deciphering,integrity protection, header compression, mobility control functions(e.g., handover, dual connectivity), inter-cell interferencecoordination, connection setup and release, load balancing, distributionfor non-access stratum (NAS) messages, NAS node selection,synchronization, RAN sharing, multimedia broadcast multicast service(MBMS), subscriber and equipment trace, RAN information management(RIM), paging, positioning, and delivery of warning messages. The basestations 102 may communicate with each other directly or indirectly(e.g., through the EPC/NGC) over backhaul links 134, which may be wiredor wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. In an aspect, although notshown in FIG. 1, geographic coverage areas 110 may be subdivided into aplurality of cells (e.g., three), or sectors, each cell corresponding toa single antenna or array of antennas of a base station 102. As usedherein, the term “cell” or “sector” may correspond to one of a pluralityof cells of a base station 102, or to the base station 102 itself,depending on the context.

While neighboring macro cell geographic coverage areas 110 may partiallyoverlap (e.g., in a handover region), some of the geographic coverageareas 110 may be substantially overlapped by a larger geographiccoverage area 110. For example, a small cell base station 102′ may havea geographic coverage area 110′ that substantially overlaps with thegeographic coverage area 110 of one or more macro cell base stations102. A network that includes both small cell and macro cells may beknown as a heterogeneous network. A heterogeneous network may alsoinclude Home eNBs (HeNBs), which may provide service to a restrictedgroup known as a closed subscriber group (CSG). The communication links120 between the base stations 102 and the UEs 104 may include uplink(UL) (also referred to as reverse link) transmissions from a UE 104 to abase station 102 and/or downlink (DL) (also referred to as forward link)transmissions from a base station 102 to a UE 104. The communicationlinks 120 may use MIMO antenna technology, including spatialmultiplexing, beamforming, and/or transmit diversity. The communicationlinks may be through one or more carriers. Allocation of carriers may beasymmetric with respect to DL and UL (e.g., more or less carriers may beallocated for DL than for UL).

The wireless communications system 100 may further include a wirelesslocal area network (WLAN) access point (AP) 150 in communication withWLAN stations (STAs) 152 via communication links 154 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may performa clear channel assessment (CCA) prior to communicating in order todetermine whether the channel is available.

The small cell base station 102′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 102′ may employ LTE or 5Gtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 150. The small cell base station 102′, employing LTE /5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. LTE in an unlicensed spectrummay be referred to as LTE-unlicensed (LTE-U), licensed assisted access(LAA), or MulteFire.

The wireless communications system 100 may further include a mmW basestation 180 that may operate in mmW frequencies and/or near mmWfrequencies in communication with a UE 182. Extremely high frequency(EHF) is part of the RF in the electromagnetic spectrum. EHF has a rangeof 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10millimeters. Radio waves in this band may be referred to as a millimeterwave. Near mmW may extend down to a frequency of 3 GHz with a wavelengthof 100 millimeters. The super high frequency (SHF) band extends between3 GHz and 30 GHz, also referred to as centimeter wave. Communicationsusing the mmW/near mmW radio frequency band have high path loss and arelatively short range. The mmW base station 180 may utilize beamforming184 with the UE 182 to compensate for the extremely high path loss andshort range. Further, it will be appreciated that in alternativeconfigurations, one or more base stations 102 may also transmit usingmmW or near mmW and beamforming. Accordingly, it will be appreciatedthat the foregoing illustrations are merely examples and should not beconstrued to limit the various aspects disclosed herein.

The wireless communications system 100 may further include one or moreUEs, such as UE 190, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. In the embodiment of FIG. 1, UE 190 has a D2DP2P link 192 with one of the UEs 104 connected to one of the basestations 102 (e.g., through which UE 190 may indirectly obtain cellularconnectivity) and a D2D P2P link 194 with WLAN STA 152 connected to theWLAN AP 150 (through which UE 190 may indirectly obtain WLAN-basedInternet connectivity). In an example, the D2D P2P links 192-194 may besupported with any well-known D2D radio access technology (RAT), such asLTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth, and so on.

According to various aspects, FIG. 2A illustrates an example wirelessnetwork structure 200. For example, a Next Generation Core (NGC) 210 canbe viewed functionally as control plane functions 214 (e.g., UEregistration, authentication, network access, gateway selection, etc.)and user plane functions 212, (e.g., UE gateway function, access to datanetworks, IP routing, etc.) which operate cooperatively to form the corenetwork. User plane interface (NG-U) 213 and control plane interface(NG-C) 215 connect the gNB 222 to the NGC 210 and specifically to thecontrol plane functions 214 and user plane functions 212. In anadditional configuration, an eNB 224 may also be connected to the NGC210 via NG-C 215 to the control plane functions 214 and NG-U 213 to userplane functions 212. Further, eNB 224 may directly communicate with gNB222 via a backhaul connection 223. Accordingly, in some configurations,the New RAN 220 may only have one or more gNBs 222, while otherconfigurations include one or more of both eNBs 224 and gNBs 222. EithergNB 222 or eNB 224 may communicate with UEs 240 (e.g., any of the UEsdepicted in FIG. 1, such as UEs 104, UE 182, UE 190, etc.). Anotheroptional aspect may include Location Server 230 which may be incommunication with the NGC 210 to provide location assistance for UEs240. The location server 230 can be implemented as a plurality ofstructurally separate servers, or alternately may each correspond to asingle server. The location server 230 can be configured to support oneor more location services for UEs 240 that can connect to the locationserver 230 via the core network, NGC 210, and/or via the Internet (notillustrated). Further, the location server 230 may be integrated into acomponent of the core network, or alternatively may be external to thecore network.

According to various aspects, FIG. 2B illustrates another examplewireless network structure 250. For example, an NGC 260 can be viewedfunctionally as control plane functions, an access and mobilitymanagement function (AMF) 264 and user plane functions, and a sessionmanagement function (SMF) 262, which operate cooperatively to form thecore network. User plane interface 263 and control plane interface 265connect the eNB 224 to the NGC 260 and specifically to AMF 264 and SMF262. In an additional configuration, a gNB 222 may also be connected tothe NGC 260 via control plane interface 265 to AMF 264 and user planeinterface 263 to SMF 262. Further, eNB 224 may directly communicate withgNB 222 via the backhaul connection 223, with or without gNB directconnectivity to the NGC 260. Accordingly, in some configurations, theNew RAN 220 may only have one or more gNBs 222, while otherconfigurations include one or more of both eNBs 224 and gNBs 222. EithergNB 222 or eNB 224 may communicate with UEs 204 (e.g., any of the UEsdepicted in FIG. 1, such as UEs 104, UE 182, UE 190, etc.). Anotheroptional aspect may include a location management function (LMF) 270,which may be in communication with the NGC 260 to provide locationassistance for UEs 204. The LMF 270 can be implemented as a plurality ofseparate servers (e.g., physically separate servers, different softwaremodules on a single server, different software modules spread acrossmultiple physical servers, etc.), or alternately may each correspond toa single server. The LMF 270 can be configured to support one or morelocation services for UEs 204 that can connect to the LMF 270 via thecore network, NGC 260, and/or via the Internet (not illustrated).

According to various aspects, FIG. 3 illustrates an exemplary basestation 310 (e.g., an eNB, a gNB, a small cell AP, a WLAN AP, etc.) incommunication with an exemplary UE 350 in a wireless network. In the DL,IP packets from the core network (NGC 210/EPC 260) may be provided to acontroller/processor 375. The controller/processor 375 implementsfunctionality for a radio resource control (RRC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda medium access control (MAC) layer. The controller/processor 375provides RRC layer functionality associated with broadcasting of systeminformation (e.g., MIB, SIBs), RRC connection control (e.g., RRCconnection paging, RRC connection establishment, RRC connectionmodification, and RRC connection release), inter-RAT mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC servicedata units (SDUs), re-segmentation of RLC data PDUs, and reordering ofRLC data PDUs; and MAC layer functionality associated with mappingbetween logical channels and transport channels, scheduling informationreporting, error correction, priority handling, and logical channelprioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement Layer-1 functionality associated with various signalprocessing functions. Layer-1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe UE 350. Each spatial stream may then be provided to one or moredifferent antennas 320 via a separate transmitter 318 a. Eachtransmitter 318 a may modulate an RF carrier with a respective spatialstream for transmission.

At the UE 350, each receiver 354 a receives a signal through itsrespective antenna 352. Each receiver 354 a recovers informationmodulated onto an RF carrier and provides the information to the RXprocessor 356. The TX processor 368 and the RX processor 356 implementLayer-1 functionality associated with various signal processingfunctions. The RX processor 356 may perform spatial processing on theinformation to recover any spatial streams destined for the UE 350. Ifmultiple spatial streams are destined for the UE 350, they may becombined by the RX processor 356 into a single OFDM symbol stream. TheRX processor 356 then converts the OFDM symbol stream from thetime-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe base station 310. These soft decisions may be based on channelestimates computed by the channel estimator 358. The soft decisions arethen decoded and de-interleaved to recover the data and control signalsthat were originally transmitted by the base station 310 on the physicalchannel. The data and control signals are then provided to thecontroller/processor 359, which implements Layer-3 and Layer-2functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the core network. Thecontroller/processor 359 is also responsible for error detection.

Similar to the functionality described in connection with the DLtransmission by the base station 310, the controller/processor 359provides RRC layer functionality associated with system information(e.g., MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto TBs,demultiplexing of MAC SDUs from TBs, scheduling information reporting,error correction through HARQ, priority handling, and logical channelprioritization.

Channel estimates derived by the channel estimator 358 from a referencesignal or feedback transmitted by the base station 310 may be used bythe TX processor 368 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 368 may be provided to different antenna352 via separate transmitters 354 b. Each transmitter 354 b may modulatean RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a mannersimilar to that described in connection with the receiver function atthe UE 350. Each receiver 318 b receives a signal through its respectiveantenna 320. Each receiver 318 b recovers information modulated onto anRF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the core network. Thecontroller/processor 375 is also responsible for error detection.

FIG. 4 illustrates an exemplary wireless communications system 400according to various aspects of the disclosure. In the example of FIG.4, a UE 404, which may correspond to any of the UEs described above withrespect to FIG. 1 (e.g., UEs 104, UE 182, UE 190, etc.), is attemptingto calculate an estimate of its position, or assist another entity(e.g., a base station or core network component, another UE, a locationserver, a third party application, etc.) to calculate an estimate of itsposition. The UE 404 may communicate wirelessly with a plurality of basestations 402 a-d (collectively, base stations 402), which may correspondto any combination of base stations 102 or 180 and/or WLAN AP 150 inFIG. 1, using RF signals and standardized protocols for the modulationof the RF signals and the exchange of information packets. By extractingdifferent types of information from the exchanged RF signals, andutilizing the layout of the wireless communications system 400 (i.e.,the base stations locations, geometry, etc.), the UE 404 may determineits position, or assist in the determination of its position, in apredefined reference coordinate system. In an aspect, the UE 404 mayspecify its position using a two-dimensional coordinate system; however,the aspects disclosed herein are not so limited, and may also beapplicable to determining positions using a three-dimensional coordinatesystem, if the extra dimension is desired. Additionally, while FIG. 4illustrates one UE 404 and four base stations 402, as will beappreciated, there may be more UEs 404 and more or fewer base stations402. It should also be noted that at two-dimensional andthree-dimensional positions may be determined at different times. Forexample, the two-dimensional position may initially be determined, andat a later time, altitude of the device may also be determined.

To support position estimates, the base stations 402 may be configuredto broadcast reference RF signals (e.g., Positioning Reference Signals(PRS), Cell-specific Reference Signals (CRS), Channel State InformationReference Signals (CSI-RS), synchronization signal blocks (SSB), TimingReference Signals (TRS), etc.) to UEs 404 in their coverage area toenable a UE 404 to measure reference RF signal timing differences (e.g.,OTDOA or RSTD) between pairs of network nodes and/or to identify thebeam that best excite the LOS or shortest radio path between the UE 404and the transmitting base stations 402. Identifying the LOS/shortestpath beam(s) is of interest not only because these beams cansubsequently be used for OTDOA measurements between a pair of basestations 402, but also because identifying these beams can directlyprovide some positioning information based on the beam direction.Moreover, these beams can subsequently be used for other positionestimation methods that may be enabled by precise ToA/ToF, such asround-trip time estimation based methods. Note that the UE may be ableto determine its own positioning from these measurements. Alternativelyor in addition thereto, the UE may be configured or request that thenetwork determine the UE's position based on the measurements. In otherwords, both network and UE based approaches are possible.

As used herein, a “network node” may be a base station 402, a cell of abase station 402, a remote radio head, an antenna of a base station 402,where the locations of the antennas of a base station 402 are distinctfrom the location of the base station 402 itself, or any other networkentity capable of transmitting reference signals. Further, as usedherein, a “node” may refer to either a network node or a UE.

A location server (e.g., location server 230) may send assistance datato the UE 404 that includes an identification of one or more neighborcells of base stations 402 and configuration information for referenceRF signals transmitted by each neighbor cell. Alternatively, theassistance data can originate directly from the base stations 402themselves (e.g., in periodically broadcasted overhead messages, etc.).Alternatively, the UE 404 can detect neighbor cells of base stations 402itself without the use of assistance data. The assistance data may berequested by the UE. Alternatively or in addition thereto, theassistance data may be provided to the UE unsolicited. The UE 404 (e.g.,based in part on the assistance data, if provided) can measure and(optionally) report the OTDOA from individual network nodes and/or RSTDsbetween reference RF signals received from pairs of network nodes. Usingthese measurements and the known locations of the measured network nodes(i.e., the base station(s) 402 or antenna(s) that transmitted thereference RF signals that the UE 404 measured), the UE 404 or thenetwork entity (e.g. location server, base station, etc.) can determinethe distance between the UE 404 and the measured network nodes and theUE 404 or the network entity (e.g. location server, base station, etc.)may calculate the location of the UE 404.

The term “position estimate” is used herein to refer to an estimate of aposition for a UE 404, which may be geographic (e.g., may comprise alatitude, longitude, and possibly altitude) and/or civic (e.g., maycomprise a street address, building designation, or precise point orarea within or nearby to a building or street address, such as aparticular entrance to a building, a particular room or suite in abuilding, a floor level in a building, or a landmark such as a townsquare). A position estimate may also be referred to as a “location,” a“position,” a “fix,” a “position fix,” a “location fix,” a “locationestimate,” a “fix estimate,” or by some other term. The means ofobtaining a location estimate may be referred to generically as“positioning,” “locating,” or “position fixing.” A particular solutionfor obtaining a position estimate may be referred to as a “positionsolution.” A particular method for obtaining a position estimate as partof a position solution may be referred to as a “position method” or as a“positioning method.”

The term “base station” may refer to a single physical transmissionpoint or to multiple physical transmission points that may or may not beco-located. For example, where the term “base station” refers to asingle physical transmission point, the physical transmission point maybe an antenna of the base station (e.g., base station 402) correspondingto a cell of the base station. Where the term “base station” refers tomultiple co-located physical transmission points, the physicaltransmission points may be an array of antennas (e.g., as in a MIMOsystem or where the base station employs beamforming) of the basestation. Where the term “base station” refers to multiple non-co-locatedphysical transmission points, the physical transmission points may be aDistributed Antenna System (DAS) (a network of spatially separatedantennas connected to a common source via a transport medium) or aRemote Radio Head (RRH) (a remote base station connected to a servingbase station). Alternatively, the non-co-located physical transmissionpoints may be the serving base station receiving the measurement reportfrom the UE (e.g., UE 404) and a neighbor base station whose referenceRF signals the UE is measuring. Thus, FIG. 4 illustrates an aspect inwhich base stations 402 a and 402 b form a DAS/RRH 420. For example, thebase station 402 a may be the serving base station of the UE 404 and thebase station 402 b may be a neighbor base station of the UE 404. Assuch, the base station 402 b may be the RRH of the base station 402 a.The base stations 402 a and 402 b may communicate with each other over awired or wireless link 422.

To accurately determine the position of the UE 404 using the OTDOAsand/or

RSTDs between RF signals received from pairs of network nodes, the UE404 needs to measure the reference RF signals received over the LOS path(or the shortest NLOS path where a LOS path is not available), betweenthe UE 404 and a network node (e.g., base station 402, antenna).However, RF signals travel not only by the LOS/shortest path between thetransmitter and receiver, but also over a number of other paths as theRF signals spread out from the transmitter and reflect off other objectssuch as hills, buildings, water, and the like on their way to thereceiver. Thus, FIG. 4 illustrates a number of LOS paths 410 and anumber of NLOS paths 412 between the base stations 402 and the UE 404.Specifically, FIG. 4 illustrates base station 402 a transmitting over aLOS path 410 a and an NLOS path 412 a, base station 402 b transmittingover a LOS path 410 b and two NLOS paths 412 b, base station 402 ctransmitting over a LOS path 410 c and an NLOS path 412 c, and basestation 402 d transmitting over two NLOS paths 412 d. As illustrated inFIG. 4, each NLOS path 412 reflects off some object 430 (e.g., abuilding). As will be appreciated, each LOS path 410 and NLOS path 412transmitted by a base station 402 may be transmitted by differentantennas of the base station 402 (e.g., as in a MIMO system), or may betransmitted by the same antenna of a base station 402 (therebyillustrating the propagation of an RF signal). Further, as used herein,the term “LOS path” refers to the shortest path between a transmitterand receiver, and may not be an actual LOS path, but rather, theshortest NLOS path.

In an aspect, one or more of base stations 402 may be configured to usebeamforming to transmit RF signals. In that case, some of the availablebeams may focus the transmitted RF signal along the LOS paths 410 (e.g.,the beams produce highest antenna gain along the LOS paths) while otheravailable beams may focus the transmitted RF signal along the NLOS paths412. A beam that has high gain along a certain path and thus focuses theRF signal along that path may still have some RF signal propagatingalong other paths; the strength of that RF signal naturally depends onthe beam gain along those other paths. An “RF signal” comprises anelectromagnetic wave that transports information through the spacebetween the transmitter and the receiver. As used herein, a transmittermay transmit a single “RF signal” or multiple “RF signals” to areceiver. However, as described further below, the receiver may receivemultiple “RF signals” corresponding to each transmitted RF signal due tothe propagation characteristics of RF signals through multipathchannels.

Where a base station 402 uses beamforming to transmit RF signals, thebeams of interest for data communication, between the base station 402and the UE 404, may be carrying RF signals that arrive at UE 404 withthe highest signal strength (as indicated by, e.g., the Reference SignalReceived Power (RSRP) or SINR in the presence of a directionalinterfering signal), whereas the beams of interest for positionestimation may be carrying RF signals that excite the shortest path orLOS path (e.g., a LOS path 410). In some frequency bands and for antennasystems typically used, these will be the same beams. However, in otherfrequency bands, such as mmW, where typically a large number of antennaelements can be used to create narrow transmit beams, they may not bethe same beams. As described below with reference to FIG. 5, in somecases, the signal strength of RF signals on the LOS path 410 may beweaker (e.g., due to obstructions) than the signal strength of RFsignals on an NLOS path 412, over which the RF signals arrive later dueto propagation delay.

FIG. 5 illustrates an exemplary wireless communications system 500according to various aspects of the disclosure. In the example of FIG.5, a UE 504, which may correspond to UE 404 in FIG. 4, is attempting tocalculate an estimate of its position, or to assist another entity(e.g., a base station or core network component, another UE, a locationserver, a third party application, etc.) to calculate an estimate of itsposition. The UE 504 may communicate wirelessly with a base station 502,which may correspond to one of base stations 402 in FIG. 4, using RFsignals and standardized protocols for the modulation of the RF signalsand the exchange of information packets.

As illustrated in FIG. 5, the base station 502 is utilizing beamformingto transmit a plurality of beams 511-515 of RF signals. Each beam511-515 may be formed and transmitted by an array of antennas of thebase station 502. Although FIG. 5 illustrates a base station 502transmitting five beams, as will be appreciated, there may be more orfewer than five beams, beam shapes such as peak gain, width, andside-lobe gains may differ amongst the transmitted beams, and some ofthe beams may be transmitted by a different base station.

A beam index may be assigned to each of the plurality of beams 511-515for purposes of distinguishing RF signals associated with one beam fromRF signals associated with another beam. Moreover, the RF signalsassociated with a particular beam of the plurality of beams 511-515 maycarry a beam index indicator. A beam index may also be derived from thetime of transmission, e.g., frame, slot and/or OFDM symbol number, ofthe RF signal. The beam index indicator may be, for example, a three-bitfield for uniquely distinguishing up to eight beams. If two different RFsignals having different beam indices are received, this would indicatethat the RF signals were transmitted using different beams. If twodifferent RF signals share a common beam index, this would indicate thatthe different RF signals are transmitted using the same beam. Anotherway to describe that two RF signals are transmitted using the same beamis to say that the antenna port(s) used for the transmission of thefirst RF signal are spatially quasi-collocated with the antenna port(s)used for the transmission of the second RF signal.

In the example of FIG. 5, the UE 504 receives an NLOS data stream 523 ofRF signals transmitted on beam 513 and a LOS data stream 524 of RFsignals transmitted on beam 514. Although FIG. 5 illustrates the NLOSdata stream 523 and the LOS data stream 524 as single lines (dashed andsolid, respectively), as will be appreciated, the NLOS data stream 523and the LOS data stream 524 may each comprise multiple rays (i.e., a“cluster”) by the time they reach the UE 504 due, for example, to thepropagation characteristics of RF signals through multipath channels.For example, a cluster of RF signals is formed when an electromagneticwave is reflected off of multiple surfaces of an object, and reflectionsarrive at the receiver (e.g., UE 504) from roughly the same angle, eachtravelling a few wavelengths (e.g., centimeters) more or less thanothers. A “cluster” of received RF signals generally corresponds to asingle transmitted RF signal.

In the example of FIG. 5, the NLOS data stream 523 is not originallydirected at the UE 504, although, as will be appreciated, it could be,as are the RF signals on the NLOS paths 412 in FIG. 4. However, it isreflected off a reflector 540 (e.g., a building) and reaches the UE 504without obstruction, and therefore, may still be a relatively strong RFsignal. In contrast, the LOS data stream 524 is directed at the UE 504but passes through an obstruction 530 (e.g., vegetation, a building, ahill, a disruptive environment such as clouds or smoke, etc.), which maysignificantly degrade the RF signal. As will be appreciated, althoughthe LOS data stream 524 is weaker than the NLOS data stream 523, the LOSdata stream 524 will arrive at the UE 504 before the NLOS data stream523 because it follows a shorter path from the base station 502 to theUE 504.

As noted above, the beam of interest for data communication between abase station (e.g., base station 502) and a UE (e.g., UE 504) is thebeam carrying RF signals that arrives at the UE with the highest signalstrength (e.g., highest RSRP or SINR), whereas the beam of interest forposition estimation is the beam carrying RF signals that excite the LOSpath and that has the highest gain along the LOS path amongst all otherbeams (e.g., beam 514). That is, even if beam 513 (the NLOS beam) wereto weakly excite the LOS path (due to the propagation characteristics ofRF signals, even though not being focused along the LOS path), that weaksignal, if any, of the LOS path of beam 513 may not be as reliablydetectable (compared to that from beam 514), thus leading to greatererror in performing a positioning measurement.

While the beam of interest for data communication and the beam ofinterest for position estimation may be the same beams for somefrequency bands, for other frequency bands, such as mmW, they may not bethe same beams. As such, referring to FIG. 5, where the UE 504 isengaged in a data communication session with the base station 502 (e.g.,where the base station 502 is the serving base station for the UE 504)and not simply attempting to measure reference RF signals transmitted bythe base station 502, the beam of interest for the data communicationsession may be the beam 513, as it is carrying the unobstructed NLOSdata stream 523. The beam of interest for position estimation, however,would be the beam 514, as it carries the strongest LOS data stream 524,despite being obstructed.

FIG. 6A is a graph 600A showing the RF channel response at a receiver(e.g., UE 504) over time according to various aspects of the disclosure.Under the channel illustrated in FIG. 6A, the receiver receives a firstcluster of two RF signals on channel taps at time T1, a second clusterof five RF signals on channel taps at time T2, a third cluster of fiveRF signals on channel taps at time T3, and a fourth cluster of four RFsignals on channel taps at time T4. In the example of FIG. 6A, becausethe first cluster of RF signals at time T1 arrives first, it is presumedto be the LOS data stream (i.e., the data stream arriving over the LOSor the shortest path), and may correspond to the LOS data stream 524.The third cluster at time T3 is comprised of the strongest RF signals,and may correspond to the NLOS data stream 523. Seen from thetransmitter's side, each cluster of received RF signals may comprise theportion of an RF signal transmitted at a different angle, and thus eachcluster may be said to have a different angle of departure (AoD) fromthe transmitter. FIG. 6B is a diagram 600B illustrating this separationof clusters in AoD. The RF signal transmitted in AoD range 602 a maycorrespond to one cluster (e.g., “Cluster1”) in FIG. 6A, and the RFsignal transmitted in AoD range 602 b may correspond to a differentcluster (e.g., “Cluster3”) in FIG. 6A. Note that although AoD ranges ofthe two clusters depicted in FIG. 6B are spatially isolated, AoD rangesof some clusters may also partially overlap even though the clusters areseparated in time. For example, this may arise when two separatebuildings at same AoD from the transmitter reflect the signal towardsthe receiver. Note that although FIG. 6A illustrates clusters of two tofive channel taps, as will be appreciated, the clusters may have more orfewer than the illustrated number of channel taps.

As in the example of FIG. 5, the base station may utilize beamforming totransmit a plurality of beams of RF signals such that one of the beams(e.g., beam 514) is directed at the AoD range 602 a of the first clusterof RF signals, and a different beam (e.g., beam 513) is directed at theAoD range 602 b of the third cluster of RF signals. The signal strengthof clusters in post-beamforming channel response (i.e., the channelresponse when the transmitted RF signal is beamformed instead ofomni-directional) will be scaled by the beam gain along the AoD of theclusters. In that case, the beam of interest for positioning would bethe beam directed at the AoD of the first cluster of RF signals, as theyarrive first, and the beam of interest for data communications may bethe beam directed at the AoD of the third cluster of RF signals, as theyare the strongest.

In general, when transmitting an RF signal, the transmitter does notknow what path it will follow to the receiver (e.g., UE 504) or at whattime it will arrive at the receiver, and therefore transmits the RFsignal on different antenna ports with an equal amount of energy.Alternatively, the transmitter may beamform the RF signal in differentdirections over multiple transmission occasions and obtain measurementfeedback from the receiver to explicitly or implicitly determine radiopaths.

Note that although the techniques disclosed herein have generally beendescribed in terms of transmissions from a base station to a UE, as willbe appreciated, they are equally applicable to transmissions from a UEto a base station where the UE is capable of MIMO operation and/orbeamforming. Also, while beamforming is generally described above incontext with transmit beamforming, receive beamforming may also be usedin conjunction with transmit beamforming in certain embodiments.

According to various aspects, as will be apparent from the foregoingdescription, beamformed communication (including transmit beamforming,receive beamforming, and/or combinations thereof) are expected to becomemore and more widespread in many wireless network deployments, includingbut not limited to wireless networks that operate in mmW and sub-6 GHzbands. In the foregoing description, certain techniques are described toidentify and report one or more beam(s) of interest that are suitablefor position estimation such that a node may receive a sufficient numberof shortest path beams that can be accurately measured to calculate, orassist the calculation of, a position estimate associated with the node.In various use cases, this may involve measuring and reporting an OTDOAfrom individual network nodes and/or RSTDs between reference RF signalsreceived from pairs of network nodes (e.g., different base stations ordifferent antennas or transmission points belonging to the same basestation). As such, due to the unique challenges of heavy path-loss facedin mmW communication systems and other wireless networks that utilizebeamformed communication, the following description provides variousenhanced methods to support positioning in wireless networks thatutilize beamformed communications.

More particularly, in wireless networks that operate in mmW and sub-6GHz bands, beamforming may be utilized when transmitting positioningreference signals (PRS) to combat high path-loss and allow PRS receptionfrom network nodes at multiple geographically separated sites, whereineach network node may correspond to a base station, a cell of a basestation, a remote radio head, an antenna of a base station where thelocations of the antennas of a base station are distinct from thelocation of the base station itself, etc. For example, as described infurther detail, positioning accuracy may be substantially improved whenperforming OTDOA-based positioning methods based on Reference SignalTime Difference (RSTD) measurements from geographically separatednetwork nodes, wherein the accuracy may further increase as the numberof network nodes hearable at a given UE increases. Furthermore, evenfrom a single site, sending the PRS on multiple beams can be helpfulbecause different beams may travel along different paths and experiencedifferent reflections. In that context, ideal positioning accuracy maybe achieved when measurements are taken based on the LOS beam. However,the LOS beam may be blocked and/or reflected, in which case the beamwith the earliest arrival time may yield the most accurate position. Inother words, as noted above, the best beam for positioning purposes maynot always be the strongest beam (e.g., the beam with the highest RSRP),as that beam may not have the earliest arrival time. Furthermore, eventhough the LOS beam(s) may be considered ideal for positioning purposes,the LOS beam(s) may not have the earliest arrival time or may not arriveat all due to blockage, reflection, and/or other factors. As such,transmitting the PRS using multiple beams can provide substantialbenefits because the multiple beams may travel different paths andincrease the chances for an accurate position estimate. Further still,beam-sweeping may be necessary for any UEs that have not gone throughbeam training regardless of whether there is any signal blockage orreflection in order to allow those UEs to determine the appropriatebeam(s) to monitor.

According to various aspects, the approach taken in LTE and other legacywireless networks is to send PRS on a comb of frequency tones. Forexample, Orthogonal frequency division multiplexing (OFDM) is amulti-carrier modulation technique that partitions the overall systembandwidth into multiple (K) orthogonal subbands, which are also calledtones, subcarriers, and/or frequency bins, wherein a frequency comb maygenerally refer to a set of carriers. As such, there may be severalresource elements (REs) in a given OFDM symbol, whereby sending the PRSon the comb of frequency tones may mean that the PRS is sent on a subsetof the resource elements in a predefined pattern (e.g., one out of everysix resource elements such that the PRS may be sent on the firstresource element, the seventh resource element, the thirteenth resourceelement, and so on). In this manner, assuming that the channel does notsubstantially or significantly change across a few OFDM symbols, usingstaggered combs to send PRS in adjacent OFDM symbols may allow the PRSto be received on all frequency tones. However, LTE and other legacywireless networks tend to be restricted to using six (6) staggered combsin a slot (e.g., because applicable standards define certain signalssuch as Cell-specific Reference Signals (CRS) that use a specific comb,so the restriction allows that pattern to be maintained). In contrast,there may be more flexibility in wireless networks that utilizebeamforming to communicate in mmW bands, such as the New RAN 220described above. For example, denser combs may be used, which may resultin a need for fewer OFDM symbols, which may in turn enable more PRSbeams per slot (e.g., the number of staggered combs that can be used ina slot may be parameterized to any suitable value rather than beingrestricted to six). Furthermore, whereas six OFDM symbols with staggeredcombs would be needed to sample all the PRS resource elements, withdenser combs fewer OFDM symbols are needed to cover all the PRS resourceelements, which means that more PRS beams can exist in a given slot. Forexample, in the extreme case where all resource elements in the OFDMsymbols are used, only one OFDM symbol may be needed. Each successiveOFDM symbol could then be the same PRS but on a different beam, whichmeans that there could be up to fourteen (14) different beams becausethere are 14 symbols per slot.

According to various aspects, based on at least the above-mentionedfactors, there may be optimization opportunities through sharing UEbeam-switching and other positioning-related capabilities with a networknode configured to transmit one or more positioning-related referencesignals. For example, a maximum number of beam switches per slot may beindicated per frequency range for each subcarrier spacing that the UEsupports (e.g., a maximum number of beam switches per slot for a sub-6GHz frequency range, for a mmW frequency range, etc.). Even within agiven frequency range, there may be multiple bands (e.g., from 24-26 GHzmay be one band, from 26-28 GHz may be another band, etc.). In general,the maximum number of beam switches may account for both transmit (Tx)beams and receive (Rx) beams across all configured serving cells. Assuch, the current standards define the maximum number of beam switchesper slot according to a single global parameter, which does notadequately account for the notion that beam switching capabilities maydiffer in different contexts (e.g., a downlink only slot versus acombined uplink/downlink or an uplink only slot). For example, a givenUE may signal a maximum of seven (7) beam switches per slot because theUE cannot handle more than 7 beam switches in certain scenarios (e.g.,the UE may be unable to handle a total of eight beams split up into sixdownlink beams and two uplink beams, but the UE may have the ability tohandle eight beams if the beams were all downlink beams). When a singleglobal parameter is used, the UE would therefore have to use the mostconstricting capability and report a maximum of seven beam switches perslot even though the UE could potentially handle more than seven beamswitches in certain specific scenarios. Furthermore, data may bedisallowed altogether on slots that are dedicated to PRS in order tohelp to fully utilize the PRS slots for capable UEs. As such, PRS slotsmay be limited to downlink beams, meaning that more beam switches couldpotentially be handled in PRS slots. Alternatively, as noted above,because fewer OFDM symbols may be needed when denser combs are used, theremaining OFDM symbols in the slot could be used for data, which alsoincreases overall utilization of the slot. As such, because the PRSitself may be more flexible in NR networks, more flexible PRS capabilitysignaling may be desired to address the above-mentioned drawbackswhereby existing signaling to report UE positioning-related capabilitiesis substantially limited (e.g., to a single global parameter for maximumbeam switches in NR networks and to signaling the ability to supportOTDOA-based positioning and/or inter-frequency RSTD measurements in LTEnetworks). The benefits of the disclosed aspects include, among others,more flexible PRS, greater granularity control for beam switch which mayallow for a variety of different devices, etc.

According to various aspects, FIG. 7A illustrates an exemplary signalingflow 700A in which a UE 504 (e.g., the UE 350) may indicatebeam-switching and other positioning-related capabilities to a networknode 502 (e.g., the network node 310) that may be configured to transmitone or more positioning-related reference signals based on theUE-indicated capabilities. More particularly, as will be described infurther detail herein, the UE 504—e.g., the RX processor 356, thecontroller/processor 359, and/or the TX processor 368 of the UE 350—mayindicate a granular beam switch capability as a function of slot type,wherein the slot type may be based on slot contents. Accordingly, the UE504 may still signal a maximum number of beam switches, but the maximumnumber of beam switches may have more granularity than a singleparameter per band. In particular, as noted above, the UE 504 mayindicate the maximum number of beam switches as a function of slot type,wherein the UE 504—e.g., the controller/processor 359 of the UE 350—maydetermine one or more possible slot types at block 710. For example, invarious embodiments, the possible slot types may be uplink only,downlink only, mixed uplink/downlink (e.g., one or more downlink OFDMsymbols followed by a gap switching band gap and then one or more uplinkOFDM symbols, or vice versa), and/or based on a number ofdownlink/uplink switches (e.g., multiple downlink/uplink switches withgaps used in each switch between downlink/uplink frames).

Alternatively and/or additionally, the possible slot types may depend onslot contents (i.e., the signal(s) that are communicated in the slot),whereby there may be different slot types and therefore different beamswitching capabilities depending on the slot contents. For example, theUE 504 may support a certain maximum number of beam switches for slotsthat contain PRS only, and support a different maximum number of beamswitches for slots that contain PRS and other downlink signals that maybe frequency division multiplexed and/or time division multiplexed withthe PRS (e.g., the first few symbols may be used for PRS and theremaining symbols used for the other downlink signals, or a contiguousset of resource blocks assigned for PRS may take up less than the fullbandwidth such that other downlink signals can be frequency divisionmultiplexed with the PRS outside that bandwidth). Accordingly, as willbe apparent to those skilled in the art, the beam switching capabilitiesmay be different when the PRS is frequency division multiplexed and/ortime division multiplexed with one or more downlink signals, as the PRSmay be transmitted, e.g., beamswept, and the receiver may want toperform receive beamsweeping as well in order to receive eachtransmitted PRS beam with a different corresponding receive beam. Assuch, once the receiver has formed the receive beam(s) to receive thetransmitted PRS beam(s) via analog beamforming, any other signals thatare frequency division multiplexed with the PRS may also be received viathe same receive beam(s). In other examples, a slot may contain PRS andone or more uplink signals, which would require the UE 504 to receivethe PRS in the slot and then switch to an uplink (or vice versa), or thePRS may alternatively also be an uplink PRS (e.g., Sounding ReferenceSignals (SRS) used in an Uplink-Time Difference of Arrival (U-TDOA)positioning scheme).

Furthermore, in various embodiments, the content-dependent slot type(s)may not be limited to slots that contain PRS, as the slot type maydepend on other possible slot contents. For example, in variousembodiments, a given slot may contain a Physical Downlink Shared Channel(PDSCH) and/or a Physical Downlink Control Channel (PDCCH), a PhysicalUplink Shared Channel (PUSCH) and/or a Physical Uplink Control Channel(PUCCH), Channel State Information Reference Signals (CSI-RS), SRS,and/or other suitable contents. In particular, a slot that only containsPDSCH may have a different slot type relative to a slot that containsPDSCH and PDCCH, a slot that only contains PUSCH may have a differenttype than a slot that contains both PUSCH and PUCCH, and so on. Furtherstill, the slot type may depend on whether the slot contents werestatically, semi-statically, or dynamically scheduled. For example, indynamically scheduled content, the UE 504 may receive and process agrant indicating that a downlink or uplink packet is scheduled on agiven receive/transmit beam at a given time such that the UE 504 isprepared to receive or send the packet via the appropriatereceive/transmit beam at the given time. But in semi-staticallyscheduled content, the slot resources are configured ahead of time, butthe resources are activated as needed and deactivated. In general, theUE 504 may need sufficient time (provided by a scheduling delay) toprepare the appropriate beam in the appropriate direction before thegiven time, whereby the number of beam switches that the UE 504 canhandle may depend on how much time the UE 504 is given to prepare theappropriate beam. On the other hand, for content that is scheduledstatically or semi-statically, the UE 504 may know about the scheduledcontent well ahead of time. As such, if the slot contents aredynamically scheduled, the slot type may also be a function of thescheduling delay (e.g., a sufficiently large delay could be treated thesame way as semi-statically scheduled content).

As such, in various embodiments, the UE 504 may generally have a certainmaximum number of beam switches for each possible slot type determinedat block 710. Accordingly, at block 712, the UE 504—e.g., thecontroller/processor 359 of the UE 350—may determine the maximum numberof beam switches that the UE 504 can support per slot as a function ofslot type, which may be indicated to the network node 502, as depictedat 716—e.g., by the controller/processor 359 and/or the TX processor 368of the UE 350. Furthermore, in various embodiments, the beam-switchingcapability indicated at 716 may indicate the beam-switching at a highlevel of granularity (e.g., for each or one or more of the slot typesnoted above), or the beam-switching capability may be indicated moregenerally (e.g., a maximum number of PRS beam switches per slot, whichcould be separate or joint for uplink PRS beams and downlink PRS beams).

According to various aspects, referring now to block 714, the UE504—e.g., the controller/processor 359 of the UE 350—may furtherdetermine one or more PRS-specific capabilities that are related to oneor more other capabilities associated with the UE 504 (e.g., bandwidth,desired positioning accuracy, etc.), which may also be indicated to thenetwork node 502 at 716. For example, as noted above, the UE 504 mayindicate a maximum number of PRS beam switches supported per slot, whichmay be determined as a function of a total number of beam switches thatthe UE 504 can support in a given slot (e.g., if the UE 504 can supportN beam switches per slot, the UE 504 should be able to support at leastthe same number and likely more PRS beam switches per slot because thePRS is specifically configured and more easily received).

According to various aspects, the PRS-specific capabilities may bedetermined at block 714 with reference to other capabilities associatedwith the UE 504 because the PRS may potentially have differentconfigurations (e.g., a number of slots repeated, whether frequencydivision multiplexing is allowed or disallowed in PRS slots, a number ofbeams per slot, PRS bandwidth, etc.), and further because all UEs maynot be required to support all possible parameter combinations. As such,because capabilities related to various UE parameters are alreadydefined, the PRS-specific capabilities that are determined at block 714may be tied or otherwise related to such capabilities and/or parameters.For example, in various embodiments, the PRS-specific capabilities maybe related to bandwidth capabilities, a total number of beam switchessupported per slot, positioning accuracy requirements, frequencydivision multiplexed reception of multiple signals, capabilities perfrequency band, and/or other suitable capabilities. For example, if theUE 504 supports a bandwidth larger than a defined threshold, then the UE504 may also be capable of receiving wideband PRS spanning that entirebandwidth. On the other hand, if the UE 504 supports a low bandwidth(e.g., below a given threshold), the UE 504 may support up to a certainPRS bandwidth that is a function of the bandwidth supported at the UE504. Alternatively, the PRS bandwidth may be made an explicit parameter(e.g., a supported bandwidth specific to PRS, which may be differentfrom the overall bandwidth that the UE 504 supports). For example, ifthe UE 504 is in connected mode, then the UE 504 may be limited bywhichever bandwidth is larger, as the UE 504 accesses at least that muchsystem bandwidth to receive incoming communications and should thereforebe able to receive any PRS in that range. However, in idle mode, the UE504 does not have any data to receive and is instead waking upperiodically to receive some synchronization signals and possibly PRS.As such, when in idle mode, the UE 504 can open up only the PRS-specificbandwidth if the PRS-specific bandwidth is smaller than the fullbandwidth supported at the UE 504.

According to various aspects, as noted above, the PRS-specificcapabilities determined at block 714 may also be related to positioningaccuracy requirements at the UE 504. For example, in variousembodiments, the UE 504 may signal a desired positioning accuracy, whichcould be dynamic depending on context (e.g., higher accuracy may beneeded when walking versus driving, when indoors versus outdoors, whenthe UE 504 is a drone/robot that is landing/docking to a power source,etc.). As such, when the UE 504 requires greater positioning accuracy,e.g., higher accuracy in OTDOA and/or RSTD measurements, some ways toachieve the improved accuracy may be through receiving PRS from moresites, with higher power, with higher PRS bandwidth, on denser PRScombs, etc., meaning that the UE 504 must have the capability to receivePRS having such configurations. Accordingly, when the UE 504 signalscertain positioning accuracy requirements, the desired positioningaccuracy can be tied or otherwise related to certain PRS capabilities(e.g., from more sites, with higher power, with higher PRS bandwidth, ondenser PRS combs, etc.).

According to various aspects, as noted above, the PRS-specificcapabilities determined at block 714 may also be related to frequencydivision multiplexed (FDM) reception of multiple signals (e.g., wherefrequency division multiplexing of other data is allowed in PRS slots).For example, if the UE 504 supports FDM reception of transmitted orbeamswept CSI-RS (SSB) with PDSCH, then the UE 504 may also support FDMreception of transmitted or beamswept PRS with PDSCH and/or CSI-RS(SSB). In particular, in order to receive the CSI-RS (SSB) with the bestpossible beamform, the UE 504 may perform beam training to try outdifferent receive beams, some of which may be better than others. Assuch, while the UE 504 is performing the beam training to try out thedifferent receive beams, all the data received in that time will havethe same beamforming if data is FDMed with the CSI-RS (SSB) because ofthe analog beamforming constraint. During the time when the UE 504 isexperimenting with the various receive beams for the CSI-RS (SSB),reception of PDSCH packets may suffer. On the other hand, where the UE504 has two or more separate receive chains, the UE 504 may have theability to form separate receive beams to receive the CSI-RS (SSB) andthe PDSCH packets, and the same multi-signal reception capability mayapply to PRS that is frequency division multiplexed with one or moreother signals.

According to various aspects, as noted above, any of the above-mentionedPRS-specific capabilities that are related to other capabilitiesassociated with the UE 504 may also be determined at block 714 perfrequency band. For example, positioning accuracy that the UE 504 canachieve, the number of base stations that can be seen, supportedbandwidths, etc. may be different in different frequency bands (e.g.,sub-6 GHz bands versus mmW bands). As such, in various embodiments, themanner in which the above UE capabilities (e.g., supported bandwidth,positioning accuracy, FDM reception, etc.) are related to PRS-specificcapabilities could also be a function of frequency band.

According to various aspects, referring to FIG. 7A, the signaling flow700A illustrated therein will now be described from the perspective ofthe network node 502 (e.g., the network node 310) that may be configuredto transmit one or more positioning-related reference signals based onthe UE capabilities that are indicated at 716 and received by thenetwork node 502—e.g., the RX processor 370 and/or thecontroller/processor 375 of the network node 310. In general, as notedabove, the network node 502 may be a base station (e.g., a gNB), a cellof a base station, a remote radio head, an antenna of a base stationwhere the locations of the antennas of a base station are distinct fromthe location of the base station itself, etc.

The network node 502 may generally have to serve various UEs that likelyhave different capabilities (e.g., different maximum numbers of PRS beamswitches per slot). Accordingly, at block 720, the network node502—e.g., the controller/processor 375 of the network node 310—mayconfigure broadcast/multicast PRS that all or some (i.e., one or more)intended receiver UEs (including at least the UE 504) are capable ofreceiving based on the minimum required capabilities of the intendedreceiver UEs to hear the PRS. Furthermore, because the intended receiverUEs may need to receive PRS from multiple geographically separatedsites, the configuration determined at block 720 may be coordinatedacross multiple cells (e.g., all cells in a paging area or in a givengeographical deployment). Accordingly, as depicted at 724, the networknode 502—e.g., the controller/processor 375 and/or the TX processor 316of the network node 310—may broadcast/multicast the PRS configured atblock 720 to all intended receiver UEs (including at least UE 504). TheUE 504—e.g., the RX processor 356 and/or the controller/processor 359 ofthe UE 350—may receive the broadcast/multicast.

However, for UEs that may have different (e.g., greater or less)capabilities and/or accuracy requirements than the minimum provided forin the broadcast/multicast PRS configured at block 720, the network node502—e.g., the controller/processor 375 of the network node 310—mayfurther configure dedicated/unicast PRS for those UEs with the differentcapabilities and/or accuracy requirements at block 722 (e.g., additionalPRS with wider bandwidth or less PRS with narrower bandwidth). Asdepicted at 726, the network node 502—e.g., the controller/processor 375and/or the TX processor 316 of the network node 310—may further transmitthe dedicated/unicast PRS configured at block 722 to specific UE subsetsbased on capabilities and/or accuracy requirements specific to those UEsubsets. Furthermore, as will be apparent to those skilled in the art,the dedicated/unicast PRS transmitted at 726 may optionally betransmitted to the UE 504 to the extent that the UE 504 indicates at 716certain capabilities and/or accuracy requirements that place the UE 504into one or more of the appropriate subsets for which thededicated/unicast PRS was configured. In this manner, the PRSspecifically configured for higher accuracy and/or greater UEcapabilities may not waste resources across the entire cell, as thespecifically configured PRS is only transmitted to the subset(s) of UEsthat have the appropriate capabilities and/or accuracy requirements forwhich the dedicated/unicast PRS was configured.

But as seen in FIGS. 7B and 7C, each signaling flow may be performedindependently. FIG. 7B illustrates a signaling flow 700B in which the UE504 may indicate beam-switching capabilities to the network node 502based on slot types. On the other hand, FIG. 7C illustrates a signalingflow 700C in which the UE 504 may indicate beam-switching capabilitiesto the network node 502 based on one or more other capabilitiesassociated with the UE to receive signals across a number of beams. FIG.7A may be viewed as a combination of FIGS. 7B and 7C.

FIG. 8 illustrates an exemplary method 800 performed by a UE, such asthe UE 350, 504. At block 810, the UE may determine a capability for anumber of beam switches that the UE supports per slot for each slot ofone or more slots based on a slot type of that slot and/or based on oneor more other capabilities associated with the UE to receive one or moresignals across a number of beams. For example, such capabilities may bepreconfigured by OEM, the network operator, carrier, etc. Block 810 maycorrespond to blocks 710, 712, and/or 714 of FIGS. 7A, 7B, and/or 7C. Inan aspect, means to perform block 810 may include the RX processor 356and/or the controller/processor 359 of the UE 350 illustrated in FIG. 3.

The slot type may be one or more of an uplink only slot, a downlink onlyslot, or a mixed uplink and downlink slot. Alternatively or in additionthereto, the slot type may be based on a number of switches between adownlink and an uplink in a mixed uplink and downlink slot. The slottype may depend on whether the slot contains positioning referencesignals (PRS) only, the PRS and one or more downlink signals, the PRSand one or more uplink signals, one or both of Physical Downlink SharedChannel (PDSCH) and Physical Downlink Control Channel (PDCCH), one orboth of Physical Uplink Shared Channel (PUSCH) and Physical UplinkControl Channel (PUCCH), Channel State Information Reference Signals(CSI-RS), or Sounding Reference Signals (SRS). Alternatively or inaddition thereto, the slot type may depend on whether one or moresignals transmitted in the slot are semi-statically or dynamicallyscheduled. The one or more other capabilities associated with the UE mayinclude one or more of supported bandwidth, a total number of supportedbeam switches per slot, a desired positioning accuracy, or a capabilityto receive multiple signals in a single beam via frequency divisionmultiplexing. The one or more other capabilities associated with the UEmay be indicated for a particular frequency band.

At block 820, the UE may transmit, to a network node, such as thenetwork node 310, 502, capability information indicating the capabilityfor the number of beam switches that the UE supports per slot. Block 820may correspond to flow 716 of FIGS. 7A, 7B, and/or 7C. In an aspect,means to perform block 810 may include the TX processor 368 and/or thecontroller/processor 359 of the UE 350 illustrated in FIG. 3.

The capability information may indicate the number of beam switches thatthe UE supports per slot according to a maximum number of PRS beams perslot. For example, the number of beam switches that the UE supports fora slot may be any number up to the maximum number of PRS beams for theslot.

At block 830, the UE may receive, from the network node, the one or moresignals across the number of beams based on the capability indicated inthe capability information for the number of beam switches per slotassociated with a slot in which the one or more signals are received.Block 830 may correspond to flows 724 and/or 726 of FIGS. 7A, 7B, and/or7C. In an aspect, means to perform block 810 may include the RXprocessor 356 and/or the controller/processor 359 of the UE 350illustrated in FIG. 3.

The number of beams across which the one or more signals are receivedmay comprise one or more beams that are broadcasted or multicasted bythe network node to one or more intended receivers based on minimumrequired capabilities of the one or more intended receivers to receivethe one or more transmitted signals. Some or all of the intendedreceivers may be within a geographic location, such as across a cell.Alternatively or in addition thereto, the number of beams across whichthe one or more signals are received may comprise one or more beams thatare unicasted by the network node to the UE or dedicated by the networknode to a subset of UEs that includes at least the UE, based on thecapability information indicating a requirement for different accuracythan provided for in the minimum required capabilities of the one ormore intended receivers.

In an aspect, the memory 360 may be an example of a computer-readablemedium that stores computer executable instructions for one or more ofthe TX processor 368, the controller/processor 358, and/or the RXprocessor 356 of the UE 350 to perform the method 800.

FIG. 9 illustrates an exemplary method 900 performed by a network node,such as the network node 310, 502. At block 910, the network node mayconfigure broadcast/multicast PRS that all or some (i.e., one or more)intended receiver UEs (including at least the UE 504) are capable ofreceiving based on the minimum required capabilities to hear the PRS.Block 910 may correspond to block 720 of FIGS. 7A, 7B, and/or 7C. In anaspect, means to perform block 910 may include the controller/processor375 of the network node 310 illustrated in FIG. 3.

At block 920, the network node may receive capability information from aUE, such as the UE 350, 504, indicating a capability for a number ofbeam switches that the UE supports per slot for each slot of one or moreslots based on a slot type of that slot and/or based on one or moreother capabilities associated with the UE to receive one or more signalsacross a number of beams. Block 920 may correspond to flow 716 of FIGS.7A, 7B, and/or 7C. In an aspect, means to perform block 910 may includethe RX processor 370 and/or the controller/processor 375 of the networknode 310 illustrated in FIG. 3.

The slot type may be one or more of an uplink only slot, a downlink onlyslot, or a mixed uplink and downlink slot. Alternatively or in additionthereto, the slot type may be based on a number of switches between adownlink and an uplink in a mixed uplink and downlink slot. The slottype may depend on whether the slot contains positioning referencesignals (PRS) only, the PRS and one or more downlink signals, the PRSand one or more uplink signals, one or both of Physical Downlink SharedChannel (PDSCH) and Physical Downlink Control Channel (PDCCH), one orboth of Physical Uplink Shared Channel (PUSCH) and Physical UplinkControl Channel (PUCCH), Channel State Information Reference Signals(CSI-RS), or Sounding Reference Signals (SRS). Alternatively or inaddition thereto, the slot type may depend on whether one or moresignals transmitted in the slot are semi-statically or dynamicallyscheduled. The transmitted information may indicate the number of beamswitches that the UE supports per slot according to a maximum number ofPRS beams per slot. The one or more other capabilities associated withthe UE may include one or more of supported bandwidth, a total number ofsupported beam switches per slot, a desired positioning accuracy, or acapability to receive multiple signals in a single beam via frequencydivision multiplexing. The one or more other capabilities associatedwith the UE may be indicated for a particular frequency band.

At block 930, the network node may configure dedicated/unicast PRS forthose UEs that may have different (e.g., greater or less) capabilitiesand/or accuracy requirements than the minimum provided for in theminimum required capabilities, (e.g., additional PRS with widerbandwidth or less PRS with narrower bandwidth). That is, the networknode may configure dedicated/unicast PRS than the configuredbroadcast/multicast PRS. Block 930 may correspond to block 722 of FIGS.7A, 7B, and/or 7C. In an aspect, means to perform block 930 may includethe controller/processor 375 of the network node 310 illustrated in FIG.3.

At block 940, the network node may transmit, to the UE, the one or moresignals in a slot. The one or more signals may be transmitted across thenumber of beams based on the indicated capability for the number of beamswitches per slot associated with the slot in which the one or moresignals are transmitted. Block 940 may correspond to flows 724 and/or726 of FIGS. 7A, 7B, and/or 7C. In an aspect, means to perform block 940may include the TX processor 316 and/or the controller/processor 375 ofthe network node 310 illustrated in FIG. 3.

The number of beams across which the one or more signals are transmittedmay comprise one or more beams that are broadcasted or multicasted toone or more intended receivers based on the minimum requiredcapabilities of the one or more intended receivers to receive the one ormore transmitted signals. Some or all of the intended receivers may bewithin a geographic location, such as across a cell. Alternatively or inaddition thereto, the number of beams across which the one or moresignals are transmitted may comprise one or more beams that areunicasted to the UE or dedicated to a subset of UEs that includes atleast the UE, based on the capability information indicating arequirement for different accuracy than provided for in the minimumrequired capabilities of the one or more intended receivers.

In an aspect, the memory 376 may be an example of a computer-readablemedium that stores computer executable instructions for one or more ofthe TX processor 316, the controller/processor 375, and/or the RXprocessor 370 of the network node 310 to perform the method 900.

Those skilled in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those skilled in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted to departfrom the scope of the various aspects described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or other suchconfigurations).

The methods, sequences, and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in Random Access Memory (RAM), flashmemory, Read-Only Memory (ROM), Erasable Programmable ROM (EPROM),Electrically Erasable Programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of non-transitorycomputer-readable medium known in the art. An exemplary non-transitorycomputer-readable medium may be coupled to the processor such that theprocessor can read information from, and write information to, thenon-transitory computer-readable medium. In the alternative, thenon-transitory computer-readable medium may be integral to theprocessor. The processor and the non-transitory computer-readable mediummay reside in an ASIC. The ASIC may reside in a user device (e.g., a UE)or a base station. In the alternative, the processor and thenon-transitory computer-readable medium may be discrete components in auser device or base station.

In one or more exemplary aspects, the functions described herein may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on a non-transitorycomputer-readable medium. Computer-readable media may include storagemedia and/or communication media including any non-transitory mediumthat may facilitate transferring a computer program from one place toanother. A storage media may be any available media that can be accessedby a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave, then the coaxial cable, fiber opticcable, twisted pair, DSL, or wireless technologies such as infrared,radio, and microwave are included in the definition of a medium. Theterm disk and disc, which may be used interchangeably herein, includes aCompact Disk (CD), laser disc, optical disk, Digital Video Disk (DVD),floppy disk, and Blu-ray discs, which usually reproduce datamagnetically and/or optically with lasers. Combinations of the aboveshould also be included within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects, those skilledin the art will appreciate that various changes and modifications couldbe made herein without departing from the scope of the disclosure asdefined by the appended claims. Furthermore, in accordance with thevarious illustrative aspects described herein, those skilled in the artwill appreciate that the functions, steps, and/or actions in any methodsdescribed above and/or recited in any method claims appended hereto neednot be performed in any particular order. Further still, to the extentthat any elements are described above or recited in the appended claimsin a singular form, those skilled in the art will appreciate thatsingular form(s) contemplate the plural as well unless limitation to thesingular form(s) is explicitly stated.

What is claimed is:
 1. A method of a user equipment (UE), the methodcomprising: determining a capability for a number of beam switches thatthe UE supports per slot for each slot of one or more slots based on aslot type of that slot and/or based on one or more other capabilitiesassociated with the UE to receive one or more signals across a number ofbeams; transmitting, to a network node, capability informationindicating the capability for the number of beam switches that the UEsupports per slot; and receiving, from the network node, the one or moresignals across the number of beams based on the capability indicated inthe capability information for the number of beam switches per slotassociated with a slot in which the one or more signals are received. 2.The method recited in claim 1, wherein the slot type is one or more ofan uplink only slot, a downlink only slot, or a mixed uplink anddownlink slot, and/or wherein the slot type is based on a number ofswitches between a downlink and an uplink in a mixed uplink and downlinkslot.
 3. The method recited in claim 1, wherein the slot type depends onwhether the slot contains positioning reference signals (PRS) only, thePRS and one or more downlink signals, the PRS and one or more uplinksignals, one or both of a Physical Downlink Shared Channel (PDSCH) and aPhysical Downlink Control Channel (PDCCH), one or both of a PhysicalUplink Shared Channel (PUSCH) and a Physical Uplink Control Channel(PUCCH), Channel State Information Reference Signals (CSI-RS), orSounding Reference Signals (SRS), and/or wherein the slot type dependson whether one or more signals transmitted in the slot aresemi-statically or dynamically scheduled.
 4. The method recited in claim1, wherein the capability information indicates the number of beamswitches that the UE supports per slot according to a maximum number ofpositioning reference signals (PRS) beams per slot.
 5. The methodrecited in claim 1, wherein the one or more other capabilitiesassociated with the UE include one or more of supported bandwidth, atotal number of supported beam switches per slot, a desired positioningaccuracy, or a capability to receive multiple signals in a single beamvia frequency division multiplexing.
 6. The method recited in claim 1,wherein the one or more other capabilities associated with the UE areindicated in the capability information for a particular frequency band.7. The method recited in claim 1, wherein the number of beams acrosswhich the one or more signals are received comprise one or more beamsthat are broadcasted or multicasted by the network node to one or moreintended receivers based on minimum required capabilities of the one ormore intended receivers to receive the one or more transmitted signals.8. The method recited in claim 1, wherein the number of beams acrosswhich the one or more signals are received comprise one or more beamsthat are unicasted by the network node to the UE or dedicated by thenetwork node to a subset of UEs that includes at least the UE, based onthe capability information indicating a requirement for differentaccuracy than provided for in minimum required capabilities of one ormore intended receivers.
 9. A user equipment (UE), comprising: at leastone processor configured to determine a capability for a number of beamswitches supported by the UE per slot for each slot of one or more slotsbased on a slot type of that slot and/or based on one or more othercapabilities associated with the UE to receive one or more signalsacross a number of beams; a transmitter configured to transmit, to anetwork node, capability information indicating the capability for thenumber of beam switches supported by the UE per slot; and a receiverconfigured to receive, from the network node, one or more signals acrossthe number of beams based on the capability indicated in the capabilityinformation for the number of beam switches per slot associated with aslot in which the one or more signals are received.
 10. The UE recitedin claim 9, wherein the slot type is one or more of an uplink only slot,a downlink only slot, or a mixed uplink and downlink slot, and/orwherein the slot type is based on a number of switches between adownlink and an uplink in a mixed uplink and downlink slot.
 11. The UErecited in claim 9, wherein the slot type depends on whether the slotcontains positioning reference signals (PRS) only, the PRS and one ormore downlink signals, the PRS and one or more uplink signals, one orboth of a Physical Downlink Shared Channel (PDSCH) and a PhysicalDownlink Control Channel (PDCCH), one or both of a Physical UplinkShared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH),Channel State Information Reference Signals (CSI-RS), or SoundingReference Signals (SRS), and/or wherein the slot type depends on whetherone or more signals transmitted in the slot are semi-statically ordynamically scheduled.
 12. The UE recited in claim 9, wherein thecapability information indicates a supported number of beam switches perslot according to a maximum number of positioning reference signals(PRS) beams per slot.
 13. The UE recited in claim 9, wherein the one ormore other capabilities associated with the UE include one or more ofsupported bandwidth, a total number of supported beam switches per slot,a desired positioning accuracy, or a capability to receive multiplesignals in a single beam via frequency division multiplexing.
 14. The UErecited in claim 9, wherein the one or more other capabilitiesassociated with the UE are indicated in the capability information for aparticular frequency band.
 15. The UE recited in claim 9, wherein thenumber of beams across which the one or more signals are receivedcomprise one or more beams that are broadcasted or multicasted by thenetwork node to one or more intended receivers based on minimum requiredcapabilities of the one or more intended receivers to receive the one ormore transmitted signals.
 16. The UE recited in claim 9, wherein thenumber of beams across which the one or more signals are transmittedcomprise one or more beams that are unicasted by the network node to theUE or dedicated by the network node to a subset of UEs that includes atleast the UE, based on the capability information indicating arequirement for different accuracy than provided for in minimum requiredcapabilities of one or more intended receivers.
 17. A method of anetwork node, the method comprising: receiving capability informationfrom a user equipment (UE) indicating a capability for a number of beamswitches that the UE supports per slot for each slot of one or moreslots based on a slot type of that slot and/or based on one or moreother capabilities associated with the UE to receive one or more signalsacross a number of beams; and transmitting, to the UE, the one or moresignals in a slot, wherein the one or more signals are transmittedacross the number of beams based on the capability indicated in thecapability information for the number of beam switches per slotassociated with the slot in which the one or more signals aretransmitted.
 18. The method recited in claim 17, wherein the slot typeis one or more of an uplink only slot, a downlink only slot, or a mixeduplink and downlink slot, and/or wherein the slot type is based on anumber of switches between a downlink and an uplink in a mixed uplinkand downlink slot.
 19. The method recited in claim 17, wherein the slottype depends on whether the slot contains positioning reference signals(PRS) only, the PRS and one or more downlink signals, the PRS and one ormore uplink signals, one or both of a Physical Downlink Shared Channel(PDSCH) and a Physical Downlink Control Channel (PDCCH), one or both ofa Physical Uplink Shared Channel (PUSCH) and a Physical Uplink ControlChannel (PUCCH), Channel State Information Reference Signals (CSI-RS),or Sounding Reference Signals (SRS), and/or wherein the slot typedepends on whether one or more signals transmitted in the slot aresemi-statically or dynamically scheduled.
 20. The method recited inclaim 17, wherein the capability information indicates a maximum numberof beam switches that the UE supports in the slot having the definedslot type according to a maximum number of positioning reference signals(PRS) beams per slot.
 21. The method recited in claim 17, wherein theone or more other capabilities associated with the UE include one ormore of supported bandwidth, a total number of supported beam switchesper slot, a desired positioning accuracy, or a capability to receivemultiple signals in a single beam via frequency division multiplexing,and/or wherein the one or more other capabilities associated with the UEare indicated in the capability information for a particular frequencyband.
 22. The method recited in claim 17, wherein the number of beamsacross which the one or more signals are transmitted comprise one ormore beams that are broadcasted or multicasted to one or more intendedreceivers based on minimum required capabilities of the one or moreintended receivers to receive the one or more transmitted signals. 23.The method recited in claim 17, wherein the number of beams across whichthe one or more signals are transmitted comprise one or more beams thatare unicasted to the UE or dedicated to a subset of UEs that includes atleast the UE based on the capability information indicating arequirement for different accuracy than provided for in minimum requiredcapabilities of one or more intended receivers.
 24. A network node,comprising: a receiver configured to receive information from a userequipment (UE) indicating a capability for a number of beam switchesthat the UE supports per slot for each slot of one or more slots basedon a slot type of that slot and/or based on one or more othercapabilities associated with the UE to receive one or more signalsacross a number of beams; and a transmitter configured to transmit, tothe UE, the one or more signals in a slot, wherein the one or moretransmitted signals are transmitted across a number of beams based onthe capability indicated in the capability information for the number ofbeam switches per slot associated with the slot in which the one or moresignals are transmitted.
 25. The network node recited in claim 24,wherein the slot type is one or more of an uplink only slot, a downlinkonly slot, or a mixed uplink and downlink slot, and/or wherein the slottype is based on a number of switches between a downlink and an uplinkin a mixed uplink and downlink slot.
 26. The network node recited inclaim 24, wherein the slot type depends on whether the slot containspositioning reference signals (PRS) only, the PRS and one or moredownlink signals, the PRS and one or more uplink signals, one or both ofa Physical Downlink Shared Channel (PDSCH) and a Physical DownlinkControl Channel (PDCCH), one or both of a Physical Uplink Shared Channel(PUSCH) and a Physical Uplink Control Channel (PUCCH), Channel StateInformation Reference Signals (CSI-RS), or Sounding Reference Signals(SRS), and/or wherein the slot type depends on whether one or moresignals transmitted in the slot are semi-statically or dynamicallyscheduled.
 27. The network node recited in claim 24, wherein thecapability information indicates the maximum number of beam switchesthat the UE supports in the slot having the defined slot type accordingto a maximum number of positioning reference signals (PRS) beams perslot.
 28. The network node recited in claim 24, wherein the one or moreother capabilities associated with the UE include one or more ofsupported bandwidth, a total number of supported beam switches per slot,a desired positioning accuracy, or a capability to receive multiplesignals in a single beam via frequency division multiplexing, and/orwherein the one or more other capabilities associated with the UE areindicated in the capability information for a particular frequency band.29. The network node recited in claim 24, wherein the number of beamsacross which the one or more signals are transmitted comprise one ormore beams that are broadcasted or multicasted to one or more intendedreceivers based on minimum required capabilities of the one or moreintended receivers to receive the one or more transmitted signals. 30.The network node recited in claim 24, wherein the number of beams acrosswhich the one or more signals are transmitted comprise one or more beamsthat are unicasted to the UE or dedicated to a subset of UEs thatincludes at least the UE based on the capability information indicatinga requirement for different accuracy than provided for in minimumrequired capabilities of one or more intended receivers.